Field of the Invention
The present invention relates to a composition for forming a release layer, a release layer, a laminate including the release layer, a method of preparing the laminate, and a method of treating the laminate.
Background Art
In recent years, thinner, smaller, or lighter electronic appliances, such as IC cards, mobile phones, and the like, have been required. In order to meet these requirements, thin semiconductor chips should be used as semiconductor chips to be embedded. Therefore, it is known that the thickness (film thickness) of a wafer substrate, which is a base of a semiconductor chip, is currently 125 μm to 150 μm, but should be 25 μm to 50 μm for next-generation chips. Accordingly, in order to obtain a wafer substrate having the above film thickness, a process of thinning the wafer substrate is necessarily required.
Since the strength of a wafer substrate is lowered by thinning, in order to prevent the damage of the thinned wafer substrate, during a production process, a structure such as a circuit is mounted on the wafer substrate while being automatically carried in a state where a support plate is bonded to the wafer substrate. For example, the formation of a through electrode is performed on the wafer substrate by a lithography process, and the preparation of a semiconductor power device is performed by an ion diffusion process and an annealing process.
In the case where the wafer substrate and the support are strongly adhered, due to an adhesive (adhesive material), it is difficult to separate the support from the wafer substrate without damaging the structure mounted on the wafer substrate. Therefore, the very difficult development of a temporary fixing technology for achieving a strong adhesion between the wafer substrate and the support during the production process and, after the production process, separating the support from the wafer substrate without damaging the structure, such as an element, mounted on the wafer substrate has been required.
It is disclosed in JP-A-2013-235939 (published Nov. 21, 2013) that a second temporary adhesive layer composed of a thermosetting modified siloxane polymer layer attachable to or separable from a support plate is provided, and the support plate is separated from a wafer substrate by heating the second temporary adhesive layer or applying mechanical stress to the second temporary adhesive layer.
Further, it is disclosed in JP-A-2012-124467 (published Jun. 28, 2012) that a release layer containing a silsesquioxane skeleton, a siloxane skeleton or an alkoxytitanium skeleton is provided, and a support plate is separated from a wafer substrate by altering the release layer by irradiation with light.